The agency has also filed a money laundering case against the officials of a private bank branch in Kashmere Gate area here, which was recently investigated by the Income Tax department on charges of alleged irregularities in converting the scrapped currencies.

The I-T teams then had also conducted survey operations on the bank after the Delhi Police intercepted two people carrying Rs 3.5 crore cash in new currency.

They said all the cash, documents and entry registers have been seized from the premises of hawala dealers and those currency exchanges who were indulging in illegal exchange of the old notes.

"The cases are under investigation both for possible contravention of forex and money laundering laws," they said.

The searches were conducted by multiple teams of the agency in various cities like Delhi, Mumbai, Chennai, Kolkata, Gandhinagar and Bengaluru among others. As many as 100 sleuths along with police personnel took part in the operation.

In the eastern region, the agency searched at least 16 locations including six in Kolkata, two each in Bhubaneswar and Paradip (both in Odisha), Guwahati among others.

The sleuths from the Kolkata zone of the ED seized Rs 10 lakh cash in new currency from the premises of a doctor in the West Bengal capital during the said operation, even as an assortment of foreign currency worth Rs 4 lakh has been seized from the same area.

They said the agency launched the nationwide action as it was getting reports of instances of illegal exchange of old currency and stashing of new currency notes to perpetrate hawala and money laundering like activities.